US8480210B2 - Liquid jet head, liquid jet apparatus, and manufacturing method for the liquid jet head - Google Patents
Liquid jet head, liquid jet apparatus, and manufacturing method for the liquid jet head Download PDFInfo
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- US8480210B2 US8480210B2 US13/134,038 US201113134038A US8480210B2 US 8480210 B2 US8480210 B2 US 8480210B2 US 201113134038 A US201113134038 A US 201113134038A US 8480210 B2 US8480210 B2 US 8480210B2
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- Prior art keywords
- partition walls
- actuator substrate
- grooves
- liquid jet
- jet head
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/17—Ink jet characterised by ink handling
- B41J2/175—Ink supply systems ; Circuit parts therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/135—Nozzles
- B41J2/14—Structure thereof only for on-demand ink jet heads
- B41J2/14201—Structure of print heads with piezoelectric elements
- B41J2/14209—Structure of print heads with piezoelectric elements of finger type, chamber walls consisting integrally of piezoelectric material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/135—Nozzles
- B41J2/16—Production of nozzles
- B41J2/1607—Production of print heads with piezoelectric elements
- B41J2/1609—Production of print heads with piezoelectric elements of finger type, chamber walls consisting integrally of piezoelectric material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/135—Nozzles
- B41J2/14—Structure thereof only for on-demand ink jet heads
- B41J2/14201—Structure of print heads with piezoelectric elements
- B41J2/14209—Structure of print heads with piezoelectric elements of finger type, chamber walls consisting integrally of piezoelectric material
- B41J2002/14217—Multi layer finger type piezoelectric element
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/42—Piezoelectric device making
Definitions
- the present invention relates to a liquid jet head for forming an image, a character, or a thin film material on a recording medium by discharging liquid from a nozzle, and relates to a method of manufacturing the liquid jet head and to a liquid jet apparatus using the liquid jet head.
- an ink jet type liquid jet head for discharging ink droplets on recording paper or the like to render a character or graphics or for discharging a liquid material on a surface of an element substrate to form a pattern of a functional thin film.
- ink or a liquid material is supplied from a liquid tank via a supply tube to the liquid jet head, the ink is caused to fill minute space formed in the liquid jet head, and a capacity of the minute space is momentarily changed according to a drive signal to discharge liquid droplets from a nozzle which communicates to a groove.
- FIG. 11 is an exploded perspective view of an ink jet head 51 of this type (FIG. 1 of JP 2000-108361 A).
- the ink jet head 51 includes: an actuator substrate 52 including a plurality of grooves 53 formed in a surface thereof; a cover plate 56 bonded onto the actuator substrate 52 so as to cover the plurality of grooves 53 ; a manifold 57 bonded to a rear end of the actuator substrate 52 , for supplying ink into the plurality of grooves 53 ; and a nozzle plate 58 bonded to a front end of the actuator substrate 52 , the nozzle plate 58 including nozzles 58 a for discharging the ink.
- the actuator substrate 52 and partition walls 54 are made of a piezoelectric material, and the partition walls 54 are subjected to polarization processing in a normal direction of the substrate surface. Electrodes 55 are respectively formed on both side surfaces of each partition wall 54 so as to sandwich the partition wall 54 . By giving a drive signal to the electrodes 55 , the partition wall 54 slips to be deformed in a thickness direction, to thereby change internal volumes of the grooves 53 . Thus, the ink filled in the grooves 53 is caused to jet from the nozzles 58 a , and is recorded on the recording medium.
- a bending point when the partition wall 54 slips to be deformed in the thickness direction is situated at substantially half a height from a bottom surface of each groove 53 to a top surface of each partition wall 54 .
- the electrode 55 to be formed on each surface of the partition wall 54 is formed from the bottom surface of the groove 53 to 1 ⁇ 2 of the height of the partition wall 54 , or formed from 1 ⁇ 2 of the height of the partition wall 54 to the height of the top surface of the partition wall 54 .
- metal electrodes are formed on the entire surface including the side surfaces of the partition wall 54 and the bottom surface of the groove 53 by electroless plating processing. Then, a laser beam is irradiated from a direction that is oblique in the direction orthogonal to the grooves 53 with respect to the normal of the surface of the actuator substrate 52 , and the upper half of the metal electrode formed on one side surface of the partition wall 54 is removed. Next, the upper half of the metal electrode formed on the other side surface is removed by irradiating the laser beam from the opposite oblique direction.
- the metal electrodes are to be removed together by irradiating the laser beam to a large area at the time of removal, an incident angle of the laser beam irradiated to the surface differs in every position, and hence the electrodes vary in width. In order to avoid this, it is necessary to irradiate the laser beam to a small area by limiting the irradiation range.
- JP 05-318741 A describes another method of forming the electrodes 55 .
- a target wire is inserted into each of the grooves, the target wire having a diameter substantially equal to the width of each groove.
- the target wire embedded in each of the grooves is sputtered.
- metal particles sputtered from the target wire adhere to upper portions of side wall surfaces. After that, the target wire is taken out of each of the grooves.
- FIG. 12 illustrates a method of forming drive electrodes by the oblique deposition on the side surfaces of the partition walls 54 made of the piezoelectric material.
- the actuator substrate 52 is inserted into a chamber of a vacuum deposition device. First, assuming that an inclination angle ⁇ is formed between an evaporation source 59 and a normal direction n of the surface on which the partition walls 54 are formed, the actuator substrate 52 is placed so that the evaporation source 59 is substantially orthogonal to a longitudinal direction of the partition walls 54 (position P 1 ).
- each electrode 55 is formed on the top surface side situated above substantially half the height of the partition wall 54 .
- the electrodes 55 which are formed on the side surfaces of the partition walls 54 need to be formed into the same shape in the respective partition walls 54 .
- the laser beam needs to be irradiated to every side surface of each of the partition walls 54 , which requires a greater amount of time for patterning the electrodes 55 as the number of the grooves 53 of the ink jet head increases. Consequently, mass production performance is reduced. Further, a metal material is scattered to the surroundings through irradiation of the laser beam, and the scattered metal material adheres to the grooves 53 again to cause a short circuit and clogging of the nozzles.
- JP 05-318741 A it is necessary to embed a large number of target wires into a large number of the narrow grooves 53 , respectively, the target wires each having a diameter substantially equal to the width of the groove 53 .
- the mass production performance is low, and the method is not realistic.
- FIGS. 13A to 13C are sectional schematic views of the actuator substrate 52 in which the electrodes 55 are formed on the side surfaces of the partition walls 54 by the method illustrated in FIG. 12 .
- FIG. 13A is an overall view of the actuator substrate 52
- FIGS. 13B and 13C are partial sectional views respectively illustrating the left and right sides of the actuator substrate 52 .
- the electrodes 55 formed on the side surfaces of each partition wall 54 are formed deeper on the left side surface than on the right side surface.
- the electrodes 55 formed on the side surfaces of each partition wall 54 are formed deeper on the right side surface than on the left side surface.
- the direction of the evaporation source 59 that is, the inclination angle ⁇ changes depending on the position of the surface of the actuator substrate 52 .
- the inclination angle ⁇ is small and the electrode 55 is formed on a deeper portion of the side surface
- the inclination angle ⁇ is large and the electrode 55 is formed on a shallower portion of the side surface.
- FIG. 14 shows a relation between a nozzle No (nozzle position) and liquid droplet discharge rate (relative value) of the ink jet head when the electrodes 55 are formed by the oblique deposition illustrated in FIGS. 13A to 13C .
- the nozzles situated at the center portion have higher liquid droplet discharge rate than the nozzles situated at the peripheral portion. This is because an electric field is applied more efficiently to the partition walls 54 situated at the center portion than those situated at the peripheral portion.
- variations in liquid droplet discharge rate cause degradation in printing quality.
- FIGS. 15A to 15D are sectional schematic views of a discharge channel formed by the groove 53 formed in the actuator substrate 52 and by the cover plate 56 bonded onto the top surface of the actuator substrate.
- the partition walls 54 are made of the piezoelectric material, and are uniformly subjected to polarization processing in a perpendicular direction (height direction of the partition walls 54 ).
- FIGS. 15A and 15B illustrate a case where the electrode 55 is formed on each side surface on an upper side situated above substantially half a height h of the partition wall 54
- FIGS. 15C and 15D illustrate a case where the electrode 55 is formed to extend over a lower side situated below substantially half the height h of the partition wall 54 .
- FIGS. 16A and 16B are sectional schematic views of the actuator substrate 52 , and illustrate shapes of the electrodes 55 with respect to positions of the partition walls 54 .
- FIG. 16A illustrates a case where all the electrodes 55 are formed on the upper side situated above the upper halves (1 ⁇ 2) h of the partition walls 54
- FIG. 16B illustrates a case where all the electrodes 55 are formed to extend over the lower halves of the partition walls 54 .
- the electrode 55 of the partition wall 54 situated at the left end portion is deepest, and the electrodes 55 become gradually shallower toward the right end portion.
- the electrode 55 of the partition wall 54 situated at the left end portion is shallowest, and the electrodes 55 become gradually deeper toward the right end portion.
- an area of an upper half of each electric field application region Sa, in which the right and left electrodes 55 overlap each partition wall 54 becomes widest at the center portion of the actuator substrate 52 and becomes narrower toward both end portions of the actuator substrate 52 .
- the discharge rate becomes highest at the center portion as shown in FIG. 14 , and becomes lower toward both the end portions.
- the areas of the electric field application regions Sa at the upper halves of the partition walls 54 are constant, whereas electric field application regions Sb at the lower halves thereof become widest at the center portion, and become narrower toward the peripheral portion.
- the slip stress at the upper halves of the partition walls 54 is equal among the respective partition walls 54
- the slip stress at the lower halves thereof, which functions as a brake with respect to deformation of the partition walls 54 resulting from the above-mentioned stress is highest at the center portion of the actuator substrate 52 , and gradually decreases toward the peripheral portion.
- discharge rate of the ink droplets discharged from the nozzles 58 a is not constant.
- deformation drive of the partition walls 54 is accelerated and decelerated at the same time, and hence energy is consumed wastefully.
- all the electrodes 55 to be formed on the side surfaces of the partition walls 54 are formed on the upper side than the height h/2.
- each electrode 55 does not extend over a portion situated below the height h/2 of the partition wall 54 in the depth direction, and that the upper half of the electric field application region Sa is formed as wide as possible. Thus, it has been extremely difficult to form the electrode.
- the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is therefore to provide a liquid jet head which is capable of minimizing variations in discharge performance among all the channels, and which is excellent in discharge efficiency.
- a liquid jet head includes: an actuator substrate including: a plurality of grooves aligned in parallel to each other in a surface thereof; partition walls separating the plurality of adjacent grooves from each other; and drive electrodes placed on both side surfaces of each of the partition walls; a cover plate bonded onto the surface of the actuator substrate so as to cover the plurality of grooves; and a nozzle plate including nozzles communicating to the plurality of grooves, the nozzle plate being bonded onto an end surface of the actuator substrate, in which the actuator substrate includes a drive region for driving the partition walls so as to deform the partition walls, and for causing liquid filling the plurality of grooves to jet from the nozzles, in which, in the drive region, each of the partition walls is made of a piezoelectric material on a top surface side situated above substantially half a height from a bottom surface of each of the plurality of grooves to a top surface of each of the partition walls, and made of a low-permittivity material, which is lower in permittivity than
- the drive electrodes are shaped so that ranges, in which the drive electrodes are formed on the plurality of partition walls made of the low-permittivity material, gradually change from one end to another end of the actuator substrate.
- the actuator substrate has a double-layer structure made of the low-permittivity material and the piezoelectric material.
- the low-permittivity material is higher in thermal conductivity than the piezoelectric material.
- the low-permittivity material is lower in mechanical rigidity than the piezoelectric material.
- the low-permittivity material is one of a machinable ceramics and a resin material.
- a liquid jet apparatus includes: the liquid jet head according to any aspects described above; a moving mechanism for reciprocating the liquid jet head; a liquid supply tube for supplying liquid to the liquid jet head; and a liquid tank for supplying the liquid to the liquid supply tube.
- a manufacturing method for a liquid jet head includes: a first bonding step of bonding a piezoelectric substrate onto a surface of a low-permittivity substrate, to thereby form an actuator substrate, the piezoelectric substrate being made of a piezoelectric material, the low-permittivity substrate being made of a low-permittivity material which is lower in permittivity than the piezoelectric material; a groove forming step of forming a plurality of grooves aligned in parallel to each other in a surface of the actuator substrate, and forming partition walls separating the plurality of adjacent grooves from each other, each of the partition walls being made of the piezoelectric material on a top surface side situated above substantially half a height from a bottom surface of each of the plurality of grooves to a top surface of each of the partition walls, and made of the low-permittivity material on a bottom surface side situated below substantially half the height; a conductive film forming step of forming a conductive film on the surface of
- the conductive film forming step includes a step of depositing a conductive material by sputtering.
- the conductive film forming step includes an oblique deposition step of depositing a conductive material obliquely on the surface of the actuator substrate from a direction oblique to a normal of the surface of the actuator substrate.
- the manufacturing method for a liquid jet head further includes: a photosensitive resin film forming step of forming a photosensitive resin film on the surface of the actuator substrate after performing the first bonding step; and a pattern forming step of forming a pattern of the photosensitive resin film through exposure and development of the photosensitive resin film before performing the conductive film forming step, in which, in the electrode forming step, the pattern of the conductive film is formed by a lift-off method in which the photosensitive resin film is removed.
- a liquid jet head includes: an actuator substrate including: a plurality of grooves aligned in parallel to each other in a surface thereof; partition walls separating the plurality of adjacent grooves from each other; and drive electrodes placed on both side surfaces of each of the partition walls; a cover plate bonded onto the surface of the actuator substrate so as to cover the plurality of grooves; and a nozzle plate including nozzles communicating to the plurality of grooves, the nozzle plate being bonded onto an end surface of the actuator substrate, in which the actuator substrate includes a drive region for driving the partition walls so as to deform the partition walls, and for causing liquid filling the plurality of grooves to jet from the nozzles, in which, in the drive region, each of the partition walls is made of a piezoelectric material on a top surface side situated above substantially half a height from a bottom surface of each of the plurality of grooves to a top surface of each of the partition walls, and made of a low-permittivity material, which is lower in permittivity than
- a drive section for the partition walls is arranged above substantially half the height of each of the partition walls, and the drive electrodes are formed so as to extend across the piezoelectric material side of the partition walls and the low-permittivity material side.
- the low-permittivity material is interposed between one partition wall and another adjacent partition wall, and hence capacitive coupling is reduced.
- a drive signal can be prevented from leaking to the adjacent partition walls and fluctuating liquid droplet discharge characteristics of the adjacent nozzles.
- the drive electrodes do not need to be formed with high accuracy so as to align at bending positions of the partition walls, and hence it is extremely easy to form the electrodes.
- FIG. 1 is a partial exploded perspective view of a liquid jet head according to a first embodiment of the present invention
- FIGS. 2A to 2D are explanatory diagrams of an actuator substrate according to the first embodiment of the present invention.
- FIGS. 3A and 3B are schematic views of electrode wiring of the liquid jet head according to the first embodiment of the present invention.
- FIG. 4 is a characteristic chart showing a relation between a nozzle position and liquid droplet discharge rate of the liquid jet head according to the first embodiment of the present invention
- FIG. 5 is a partial exploded perspective view of a liquid jet head according to a second embodiment of the present invention.
- FIGS. 6A , 6 B, 6 C, 6 D, 6 E, and 6 F are explanatory diagrams illustrating a manufacturing method for a liquid jet head according to a third embodiment of the present invention.
- FIGS. 7A , 7 B, 7 C, and 7 D are explanatory diagrams illustrating a manufacturing method for a liquid jet head according to a fourth embodiment of the present invention.
- FIGS. 8A , 8 B, 8 C, 8 D, and 8 E are explanatory diagrams illustrating a manufacturing method for a liquid jet head according to a fifth embodiment of the present invention.
- FIGS. 9A , 9 B, 9 C, and 9 D are explanatory diagrams illustrating the manufacturing method for a liquid jet head according to the fifth embodiment of the present invention.
- FIG. 10 is an explanatory diagram illustrating a manufacturing method for a liquid jet head according to a sixth embodiment of the present invention.
- FIG. 11 is an exploded perspective view of a conventionally known ink jet head
- FIG. 12 is a schematic view illustrating an electrode forming method for a conventionally known ink jet head
- FIGS. 13A to 13C are partial sectional views of partition walls of the conventionally known ink jet head
- FIG. 14 is a characteristic chart showing a relation between a nozzle position and liquid droplet discharge rate of the conventionally known ink jet head
- FIGS. 15A to 15D are sectional schematic views illustrating deformation drive of a conventionally known discharge channel.
- FIGS. 16A and 16B are sectional schematic views of a conventionally known actuator substrate.
- a liquid jet head includes: an actuator substrate including a plurality of grooves separated from each other by partition walls, and including drive electrodes placed on both side surfaces of each of the partition walls; a cover plate bonded onto the actuator substrate so as to cover the respective grooves; and a nozzle plate including nozzles communicating to the respective grooves, the nozzle plate being bonded onto an end surface of the actuator substrate.
- the actuator substrate includes a drive region for driving the partition walls so as to deform the same, and for causing liquid filling the grooves to jet from the nozzles.
- Each partition wall in the drive region is made of a piezoelectric material on a top surface side situated above substantially half a height of the partition wall, and made of a low-permittivity material, which is lower in permittivity than the piezoelectric material, on a groove bottom surface side situated below substantially half the height. Further, each drive electrode in the drive region is placed so as to extend across each side surface of the partition wall made of the piezoelectric material and each side surface of the partition wall made of the low-permittivity material.
- the partition wall is made of the low-permittivity material on the bottom surface side situated below substantially half the height, and hence the bottom surface side does not exhibit an electrostrictive effect even when the electric field is applied thereto.
- deformation drive amounts of the respective partition walls are equalized, and it is possible to reduce variations in liquid droplet discharge rate among the nozzles.
- the low-permittivity material is interposed between one partition wall and another adjacent partition wall, and hence capacitive coupling is reduced. Owing to the reduction in capacitive coupling, leakage of a drive signal between the adjacent partition walls is reduced, with the result that liquid discharge characteristics cannot be affected by drive states of the adjacent channels.
- each drive electrode in the drive region only needs to be formed to extend across each side surface of the partition wall made of the piezoelectric material and each side surface of the partition wall made of the low-permittivity material situated below the piezoelectric material, and an extending amount does not affect the deformation drive amount of the partition wall.
- the electrode forming method is extremely simplified.
- PZT Lead zirconate titanate
- BaTiO 3 barium titanate
- the piezoelectric material is subjected to polarization processing in advance in a specific direction, for example, a normal direction of the surface of the actuator substrate.
- a glass material, a metal oxide, a ceramics, a machinable ceramics, a resin material, or the like can be used as the low-permittivity material.
- PZT As the piezoelectric material, a half or less of an amount of PZT can be used when compared to the case of the conventional method, and hence it is possible to remarkably reduce an amount of lead to be used.
- the machinable ceramics is excellent in processability, and hence the grooves can be formed easily at once in the machinable ceramics and the piezoelectric material bonded onto the surface of the machinable ceramics.
- the resin material is excellent in processability and die moldability, and hence it is possible to easily form a complex shape.
- the resin material can be used also for the cover plate which is bonded onto a top surface of the actuator substrate, and hence it is possible to remarkably reduce manufacturing cost.
- the low-permittivity material when using a material higher in thermal conductivity than the piezoelectric material as the low-permittivity material, it is possible to further improve a heat radiation effect of heat generated by deformation drive of the partition walls.
- mechanical rigidity of the low-permittivity material for example, Young's modulus thereof can be made smaller than that of the piezoelectric material. Thus, it is possible to deform and drive the partition walls at lower voltage.
- a manufacturing method for a liquid jet head includes: a first bonding step of bonding a piezoelectric substrate onto a surface of a low-permittivity substrate, to thereby form an actuator substrate; a groove forming step of forming a plurality of grooves aligned in parallel to each other in a surface of the actuator substrate, and forming partition walls separating the plurality of grooves from each other, each of the partition walls being made of a piezoelectric material on a top surface side situated above substantially half a height from a bottom surface of each of the grooves to the top surface of each of the partition walls, and made of a low-permittivity material on the bottom surface side situated below substantially half the height; a conductive film forming step of forming a conductive film on the surface of the actuator substrate and the partition walls in the drive region so that the conductive film extends across each side surface of each of the partition walls made of the piezoelectric material and each side surface of each of the partition walls made of the low-permittivity
- each of the partition walls is made of the low-permittivity material on the bottom surface side situated below substantially half the height of the partition wall, and hence the bottom surface side does not exhibit the electrostrictive effect even when the electric field is applied thereto. Accordingly, even when the drive electrode extends over the bottom surface side situated below substantially half the height of the partition wall, the extending drive electrode does not affect the deformation drive of the partition wall, and does not affect the discharge rate of liquid droplets discharged from the nozzles. With this, there is remarkably eased strictness required for pattern formation accuracy of an electrode pattern which is formed on the side surfaces of the partition walls in the conductive film forming step or the electrode forming step.
- the low-permittivity material is interposed between one partition wall and another adjacent partition wall, and hence it is possible to reduce leakage of the drive signal.
- the manufacturing method may further include a photosensitive resin film forming step of forming a photosensitive resin film on the surface of the actuator substrate after performing the bonding step, and include a pattern forming step of forming a pattern through exposure and development of the photosensitive resin film before performing the conductive film forming step.
- a pattern of the conductive film can be formed by a lift-off method in which the photosensitive resin film is removed to form the above-mentioned pattern. In this way, it is possible to easily form an electrode pattern on the surface of the actuator substrate and the top surface of each partition wall.
- FIG. 1 is a partial exploded perspective view of a liquid jet head 1 according to a first embodiment of the present invention, and a side surface on a front side illustrates a vertical cross-section along grooves 6 .
- FIGS. 2A to 2D are explanatory diagrams of an actuator substrate 2 to be used in the first embodiment.
- FIG. 2A is a vertical sectional schematic view taken along a direction of the grooves 6
- FIG. 2B is a vertical sectional schematic view of a part AA
- FIGS. 2C and 2D are partial enlarged views illustrating a left side and a right side of the vertical cross-section of the part AA.
- the liquid jet head 1 includes the actuator substrate 2 , a cover plate 3 bonded on the actuator substrate 2 , and a nozzle plate 4 bonded to end surfaces of the actuator substrate 2 and the cover plate 3 at front ends FE thereof.
- the actuator substrate 2 has a configuration in which an upper substrate made of a piezoelectric material 10 is pasted on a lower substrate made of a low-permittivity material 9 .
- a surface of the actuator substrate 2 on the cover plate 3 side includes the plurality of grooves 6 formed in parallel from the front end FE to some midpoint between the front end FE and a rear end RE, and includes a plurality of partition walls 7 separating the respective grooves 6 .
- each of the grooves 6 is made of the piezoelectric material 10 on a top surface side (second portion of partition wall 7 ) situated above substantially half a height h from a bottom surface 12 of the groove 6 to a top surface 13 of the partition wall 7 , and made of the low-permittivity material 9 , which is lower in permittivity than the piezoelectric material 10 , on the bottom surface side (first portion of partition wall 7 ) situated below substantially half the height h.
- Both side surfaces of the partition wall 7 respectively include drive electrodes 11 L and 11 R for driving the partition wall 7 so as to deform the same.
- confronting side surfaces of each pair of adjacent partition walls 7 are provided with confronting drive electrodes 11 R, 11 L which are not electrically connected to one another, as can be seen from FIGS. 2B-2D in which the drive electrodes are not formed on bottom surfaces 12 of the groove 6 .
- Each of the drive electrodes 11 covers at least the entire side surface made of the piezoelectric material 10 .
- the drive electrode 11 formed on each side surface of the partition wall 7 is electrically connected to a terminal electrode 17 formed on a surface at the vicinity of the rear end RE of the actuator substrate 2 , and electrically connected to a wiring electrode (not shown) of a flexible substrate 5 bonded to the top surface at the rear end RE of the actuator substrate 2 .
- the cover plate 3 includes a liquid supply hole 16 through which liquid is supplied into the respective grooves 6 .
- the nozzle plate 4 includes nozzles 8 which communicate to channels formed by the cover plate 3 and the grooves 6 , and is bonded on the end surfaces of the actuator substrate 2 and the cover plate 3 at the front ends FE thereof.
- a drive signal generated by a drive circuit (not shown) is given to the drive electrodes 11 L and 11 R formed on both the side surfaces of the partition walls 7 through the wiring electrode (not shown) of the flexible substrate 5 .
- the partition walls 7 are deformed according to the drive signal, to thereby change internal volumes of the grooves 6 . In this way, liquid filling the channels is discharged from the nozzles 8 as liquid droplets.
- the top surfaces 13 of the partition walls 7 are bonded and fixed to the cover plate 3 at a region ranging from the front end FE to the liquid supply hole 16 , and hence the partition walls 7 are deformed.
- the region to be deformed is referred to as a drive region DR.
- deformation of the piezoelectric material 10 as a substantially upper half of the partition wall 7 is described.
- a drive voltage is applied to the piezoelectric material 10 of the partition wall 7 through the drive electrodes 11 , the cross-section of the piezoelectric material 10 is deformed from a substantially rectangular shape into a substantially parallelogram shape.
- the piezoelectric material 10 is deformed into a substantially parallelogram shape in which the top surface 13 serves as an upper side and a portion bonded to the low-permittivity material 9 serves as a lower side.
- deformation of the low-permittivity material 9 as a substantially lower half of the partition wall 7 is described. Unlike the above-mentioned deformation of the piezoelectric material 10 , piezoelectric deformation does not occur in the low-permittivity material 9 , and hence the low-permittivity material 9 is deformed following the deformation of the piezoelectric material 10 .
- substantially the center of the partition wall 7 is fixed to the piezoelectric material 10 , and hence is deformed following the deformation thereof.
- the lowermost portion of the partition wall 7 is fixed by the low-permittivity material 9 , and hence is not deformed.
- the upper half and the lower half of the partition wall 7 are deformed into a substantially parallelogram shape so as to be vertically symmetric about substantially the center of the partition wall, and hence the partition wall 7 is deformed into a “dogleg shape” in an overall view.
- the deformation of the partition wall 7 changes the internal volumes of the grooves 6 , and as described above, liquid filling the channels is discharged from the nozzles 8 as liquid droplets.
- the drive region DR is normally set to a region in which the depth of each of the grooves 6 is deep and the bottom surface 12 thereof is flat. Therefore, a “height of the partition wall in the drive region from the top surface to the bottom surface of the groove” refers to a height from the flat bottom surface 12 of each of the grooves 6 to the top surface 13 , that is, the height h at which the partition wall 7 becomes highest.
- the drive region DR may sometimes extend to a region in which the bottom surface 12 of each of the grooves 6 is inclined, or formed into an arc shape with a trace of a shape of a dicing blade.
- the “height of the partition wall in the drive region from the bottom surface of the groove to the top surface” refers to the height excluding the region in which the bottom surface 12 of each of the grooves 6 is inclined and the region in which there is the trace of an arc shape, that is, the height h, at which the partition wall 7 becomes highest, from the flat bottom surface 12 of each of the grooves 6 to the top surface 13 .
- the shapes of the partition walls 7 and the shapes of the drive electrodes 11 are described.
- the drive electrodes 11 are formed by depositing a conductive material by oblique deposition.
- widths in a depth direction of the drive electrodes 11 are unequal.
- the drive electrodes 11 L on the left side surfaces are larger in width in the depth direction than the drive electrodes 11 R on the right side surfaces.
- the drive electrodes 11 R on the right side surfaces are larger in width in the depth direction than the drive electrodes 11 L on the left side surfaces.
- the drive electrodes 11 of each of the partition walls 7 gradually change from the shapes of the drive electrodes 11 L and 11 R illustrated in FIG. 2C to the shapes of the drive electrodes 11 L and 11 R illustrated in FIG. 2D . That is, the drive electrodes 11 formed on the side surfaces of each partition wall 7 overlap the entire side surfaces of the piezoelectric material 10 situated above substantially half the height h, whereas the drive electrodes 11 have unequal shapes in the depth direction on the side surfaces of the low-permittivity material 9 .
- the piezoelectric material 10 exhibits an electrostrictive effect.
- the piezoelectric material 10 of each partition wall 7 is arranged at substantially half the height h above the bottom surface 12 of each groove 6 .
- the point at substantially half the height h serves as a bending point, and hence can most efficiently develop bending deformation with respect to electric field energy.
- the low-permittivity material 9 is interposed between one partition wall 7 and another adjacent partition wall 7 .
- the respective partition walls 7 have substantially the same deformation amount when an electric field is applied on the drive electrodes 11 L and 11 R of the partition walls 7 , and an influence of drive of the adjacent partition walls 7 is reduced.
- the drive electrodes 11 of each partition wall 7 gradually change from the shape of the drive electrodes 11 L and 11 R illustrated in FIG. 2C to the shape of the drive electrodes 11 L and 11 R illustrated in FIG. 2D . More specifically, ranges, in which the drive electrodes on one side of the actuator substrate 2 are formed on the low-permittivity material 9 , gradually change from one end to the other end of the actuator substrate 2 (from the left direction to the right direction of the drawing sheet of FIGS. 2B to 2D ). Assuming that the drive electrodes 11 L illustrated in FIGS. 2C and 2D are the drive electrodes on one side, those shapes can be understood well with reference to FIGS. 3A and 3B and FIGS. 7A , 7 B, 7 C, and 7 D described below, and it is understood that the ranges, in which the drive electrodes 11 L are formed on the low-permittivity material 9 , change to become gradually smaller.
- ranges, in which the drive electrodes on the other side of the actuator substrate 2 are formed on the low-permittivity material 9 gradually change from the other end to one end of the actuator substrate 2 (from the right direction to the left direction of the drawing sheet of FIGS. 2B to 2D ).
- the drive electrodes 11 R illustrated in FIGS. 2C and 2D are the drive electrodes on the other side, those shapes can be understood well with reference to FIGS. 3A and 3B and FIGS. 7A , 7 B, 7 C, and 7 D described below, and it is understood that the ranges in which the drive electrodes 11 R are formed on the low-permittivity material 9 change to become gradually smaller.
- FIGS. 3A and 3B are schematic views illustrating the electrode wiring of the liquid jet head 1 according to the first embodiment.
- FIG. 3A illustrates the electrode wiring for one-cycle drive
- FIG. 3B illustrates the electrode wiring for three-cycle drive.
- the actuator substrate 2 is made of the piezoelectric material 10 on the cover plate 3 side situated above substantially half the height of each of the partition walls 71 to 77 , and made of the low-permittivity material 9 on the bottom surface 12 side situated below substantially half the height thereof.
- the drive electrodes 11 overlap both the entire side surfaces of the piezoelectric material 10 , but have unequal extending widths that extend over the low-permittivity material 9 side.
- dummy channels D 1 to D 4 and discharge channels C 1 to C 4 are alternately arranged.
- the dummy channels D 1 to D 4 are not filled with liquid, whereas the discharge channels C 1 to C 4 are filled with liquid.
- the drive electrodes 11 formed on both the partition walls of the discharge channels C 1 to C 4 are connected to a GND mutually.
- the drive electrodes 11 formed on the side surfaces on the discharge channel side of the dummy channels D 1 to D 4 adjacent to the discharge channels C 1 to C 4 are respectively connected to terminals Ta to Td that input the drive signal.
- the drive signal is given to the terminal Ta. Then, both the partition walls 71 and 72 are deformed so as to be symmetric about the discharge channel C 1 , and liquid filling the discharge channel C 1 is discharged from the corresponding nozzle 8 of the nozzle plate 4 (not shown).
- the other discharge channels are driven similarly. In other words, it is possible to simultaneously discharge liquid droplets from the respective discharge channels C 1 to C 4 at the same timing.
- the channels C 1 to C 7 are filled with liquid.
- the drive electrodes 11 formed on both the partition walls of the respective channels C 1 to C 7 are respectively connected to terminal T 1 to T 7 .
- the channels C 1 , C 4 , and C 7 are selected at a first cycle timing
- the channels C 2 and C 5 are selected at a second cycle timing
- the channels C 3 and C 6 are selected at a third cycle timing. Thereafter, the selections are performed repeatedly. For example, when driving the channel C 1 at the first timing, the terminal T 1 is connected to the GND, and the drive signal is given to terminals T 0 and T 2 .
- both the partition walls 71 and 72 are deformed so as to be symmetric about the channel C 1 , and liquid filling the channel C 1 is discharged from the corresponding nozzle 8 of the nozzle plate 4 (not shown).
- the terminal T 2 is connected to the GND, and the drive signal is given to terminals T 1 and T 3 .
- both the partition walls 72 and 73 are deformed so as to be symmetric about the channel C 2 , and liquid filling the channel C 2 is discharged from the corresponding nozzle 8 of the nozzle plate 4 (not shown). Thereafter, driving is performed repeatedly in order of the third cycle, the first cycle . . . .
- deformation drive amounts of the partition walls 71 to 77 are equalized, and it is possible to reduce variations in liquid droplet discharge rate among the nozzles.
- the low-permittivity material 9 is interposed between one partition wall and another adjacent partition wall, and hence capacitive coupling is reduced. Consequently, the drive signal does not leak to the adjacent partition walls, and liquid discharge characteristics do not fluctuate.
- FIG. 4 is a graph showing a relation between liquid droplet discharge rate (relative value) and a nozzle No (nozzle position) of the liquid jet head 1 described in the first embodiment.
- the vertical axis represents liquid droplet discharge rate
- the horizontal axis represents the nozzle No
- the same scale as that of a conventional example illustrated in FIG. 14 is used.
- the liquid droplet discharge rate flattens out with respect to the nozzle No (nozzle position), and it is possible to understand that equality of discharge rate is remarkably improved in comparison with the conventional example illustrated in FIG. 14 .
- a PZT ceramics is used as the piezoelectric material 10
- a machinable ceramics is used as the low-permittivity material 9 .
- the machinable ceramics for example, Macerite, Macor, Photoveel, Shapal (which are all registered trademarks) may be used.
- the PZT ceramics has a relative permittivity of 2000 or more, a Young's modulus of 70 GPa to 80 GPa, which indicates rigidity, and a thermal conductivity of 1 W/m ⁇ K to 1.5 W/m ⁇ K.
- the machinable ceramics may have a relative permittivity of 10 or less (for example, a paraelectric material having a relative permittivity of 5 to 6), and have a Young's modulus of from 50 MPa to less than 70 MPa, and a thermal conductivity of 1.5 W/m ⁇ K to 90 W/m ⁇ K.
- a relative permittivity of 10 or less for example, a paraelectric material having a relative permittivity of 5 to 6
- a Young's modulus of from 50 MPa to less than 70 MPa, and a thermal conductivity of 1.5 W/m ⁇ K to 90 W/m ⁇ K.
- the thermal conductivity is increased, and hence it is possible to improve a heat radiation effect.
- the bending point of each partition wall 7 is situated near a boundary between the low-permittivity material 9 and the piezoelectric material 10 , in other words, the bending point is situated at the uniform point, i.e., at substantially half the height h above the bottom surface 12 of the groove 6 , and the deformation amount of the partition wall 7 with respect to the electric field is uniform. Consequently, it is possible to reduce variations in liquid droplet discharge rate.
- the method of forming the drive electrodes 11 is not limited to the method of depositing the conductive material by oblique deposition, but may be a method of forming a conductive film by deposition, sputtering, plating, or the like and then patterning the conductive film.
- a material having a coefficient of thermal expansion nearly equal to that of the piezoelectric material 10 can be used, and, for example, the same material as the piezoelectric material 10 can be used.
- the low-permittivity material 9 has the thermal conductivity that is one digit larger than that of the PZT ceramics, and hence it is possible to effectively cool the piezoelectric material 10 and the grooves 6 .
- the resin material allows a complex shape to be easily formed by a molding method, and hence it is possible to remarkably reduce manufacturing cost.
- FIG. 5 is a schematic partial perspective view of the liquid jet head 1 according to a second embodiment of the present invention.
- the second embodiment is different from the first embodiment in that the plurality of grooves 6 formed in the surface of the actuator substrate 2 extend from the front end FE up to the rear end RE.
- the same portions and the portions having the same function are denoted by the same reference symbols.
- the liquid jet head 1 includes the actuator substrate 2 , the cover plate 3 bonded on the actuator substrate 2 , and the nozzle plate 4 bonded to the end surfaces of the actuator substrate 2 and the cover plate 3 at the front ends FE thereof.
- the actuator substrate 2 has a configuration in which the upper substrate made of the piezoelectric material 10 is pasted on the lower substrate made of the low-permittivity material 9 .
- the surface of the actuator substrate 2 includes the plurality of grooves 6 formed from the front end FE up to the rear end RE, and includes the plurality of partition walls 7 separating the grooves 6 .
- Each of the grooves 6 is made of the piezoelectric material 10 on the top surface 13 side situated above substantially half the height h from the bottom surface 12 of the groove 6 to the top surface 13 of the partition wall 7 , and made of the low-permittivity material 9 on the bottom surface 12 side situated below substantially half the height h.
- Both of the side surfaces of the partition wall 7 respectively include the drive electrodes 11 for driving the partition wall 7 so as to deform the same.
- Each of the drive electrodes 11 overlaps at least the entire side surface of the piezoelectric material 10 on the channel side.
- the drive electrodes 11 of each partition wall 7 are connected to the terminal electrodes 17 formed on the top surface 13 of the partition wall 7 at the vicinity of the rear end RE. That is, the drive electrode 11 formed on one side surface of the partition wall 7 is electrically connected to a terminal electrode 17 a formed on the top surface 13 on the one side surface side, and the drive electrode 11 formed on the other side surface is electrically connected to a terminal electrode 17 b formed on the top surface 13 on the other side surface side.
- the terminal electrodes 17 a and 17 b formed at the vicinity of the rear end RE are electrically connected to the wiring electrode (not shown) of the flexible substrate 5 bonded to the top surface at the rear end RE of the actuator substrate 2 .
- the cover plate 3 includes the liquid supply hole 16 through which liquid is supplied into the grooves 6 , and the cover plate 3 is bonded to the surface of the actuator substrate 2 so as to cover the surface from the front end FE to before the rear end RE.
- the respective grooves 6 are sealed by a sealing material (not shown) on the rear end RE side with respect to the liquid supply hole 16 . With this configuration, the liquid supplied from the liquid supply hole 16 into the grooves 6 does not flow out to the rear end RE side through the grooves 6 .
- the nozzle plate 4 includes the nozzles 8 which communicate to the channels formed by the cover plate 3 and the grooves 6 , and is bonded on the end surface at the front end FE of the cover plate 3 .
- the grooves 6 are formed straight in parallel with one another from the front end FE to the rear end RE, and hence it is possible to eliminate slanted portions of the bottom surfaces 12 of the grooves 6 , and to achieve downsizing of the actuator substrate 2 .
- the drive region DR is situated on the front end FE side with respect to the liquid supply hole 16 of the cover plate 3 .
- the adjacent partition walls 7 are fixed through the low-permittivity material 9 , and hence a leakage electric field caused by capacitive coupling is reduced, with the result that the partition walls 7 can be driven without being influenced by the drive signal supplied to the adjacent partition walls.
- the drive electrodes 11 overlap at least the entire side surfaces made of the piezoelectric material 10 , and hence the respective partition walls 7 have substantially the same deformation amount at the time of driving. As a result, discharge rate of liquid droplets discharged from the nozzles 8 at the time of driving is equalized in the respective channels.
- the cover plate 3 is bonded so as to cover the plurality of grooves 6 of the actuator substrate 2 without providing the liquid supply hole 16 in the cover plate 3 , and a manifold for liquid supply is placed at the rear end RE, to thereby supply liquid into the respective grooves 6 from the rear end RE side.
- Materials and the like used as the piezoelectric material 10 and the low-permittivity material 9 are similar to those of the first embodiment, and hence description thereof is omitted.
- FIGS. 6A , 6 B, 6 C, 6 D, 6 E, and 6 F are explanatory diagrams illustrating a manufacturing method for a liquid jet head according to a third embodiment of the present invention.
- the same portions and the portions having the same function are denoted by the same reference symbols.
- FIG. 6A illustrates a cross-section of the actuator substrate 2 which has undergone a first bonding step of bonding a piezoelectric substrate made of the piezoelectric material 10 on a surface of a low-permittivity substrate made of the low-permittivity material 9 which is lower in permittivity than the piezoelectric material 10 .
- a machinable ceramics is used as the low-permittivity material 9
- a PZT ceramics is used as the piezoelectric material 10 . Both the materials are pasted and bonded to each other by an adhesive.
- the piezoelectric substrate has a thickness corresponding to a half of the depth of the grooves 6 to be formed later.
- the piezoelectric substrate having a thickness larger than the half of the depth of the grooves 6 may be bonded on the low-permittivity substrate, and then may be ground so as to have the thickness corresponding to the half of the depth of the grooves 6 .
- the thickness of the piezoelectric substrate is large, and hence it is easy to handle the substrate when pasting on the low-permittivity substrate.
- the thickness of the piezoelectric substrate is set to 150 ⁇ m.
- the machinable ceramics is the low-permittivity material having a relative permittivity of 10 or less, and excellent in machinability.
- Macerite, Macor, Photoveel, and Shapal which are all registered trademarks
- an aluminum nitride or an aluminum nitride-based machinable ceramics may be used as the low-permittivity material 9 .
- Each of the materials has a relative permittivity of 10 or less, and is a highly thermal conductive material. Thus, it is possible to effectively cool the piezoelectric material 10 which generates heat at the time of driving.
- FIGS. 6B and 6C illustrate a groove forming step of forming a plurality of parallelly aligned grooves by cutting the surface of the actuator substrate 2 .
- FIG. 6B is a vertical sectional schematic view taken along a direction of the grooves 6 of the actuator substrate 2
- FIG. 6C is a vertical sectional schematic view taken along a direction orthogonal to the grooves 6 .
- a rotating dicing blade 19 is lowered onto the surface of the actuator substrate 2 , and then moved to form the plurality of parallelly aligned grooves 6 .
- Each of the partition walls 7 separating the adjacent grooves 6 is made of the piezoelectric material 10 on the top surface 13 side situated above substantially half the height from the bottom surface 12 of the groove 6 to the top surface 13 of the partition walls 7 , and is made of the low-permittivity material 9 on the bottom surface 12 side situated below substantially half the height.
- the depth of the grooves 6 i.e., the height from the bottom surface 12 to the top surface 13 is set to 300 ⁇ m to 360 ⁇ m, and the grooves 6 constituting 100 or more channels are formed.
- a large number of the actuator substrates 2 are formed simultaneously.
- the grooves 6 are cut along a broken line 6 ′ like a ship's bottom, and then are divided at a center portion BB after performing a second bonding step described below, to thereby obtain the plurality of liquid jet heads 1 .
- FIG. 6D is a sectional schematic view of the actuator substrate 2 which has undergone a conductive film forming step of forming a conductive film 20 on the surface of the actuator substrate 2 and both the side surfaces of each partition wall 7 .
- the conductive film 20 can be formed of a metal material such as aluminum, gold, Cr, or Ni by sputtering, deposition, plating, or the like.
- FIG. 6E is a sectional schematic view of the actuator substrate 2 which has undergone an electrode forming step of patterning the conductive film 20 and forming the drive electrodes 11 from the conductive film 20 formed on each partition wall 7 .
- a pattern of a photosensitive resin film is formed by photolithography, and the conductive film 20 is removed by etching. Further, it is possible to form a pattern of the conductive film 20 by a laser beam and a lift-off method described below instead of by the photolithography and the etching processing.
- the drive electrodes 11 formed on the side surfaces of both the partition walls 7 forming the groove 6 are connected to each other at the bottom surface 12 of the groove 6 .
- the drive electrodes 11 may be separated from each other by cutting the conductive film 20 formed on the bottom surface 12 of the groove 6 at the center portion of the bottom surface 12 by the laser beam or a dicing blade having a thickness smaller than the width of the groove 6 .
- FIG. 6F is a sectional schematic view of the liquid jet head 1 which has undergone the second bonding step of bonding the cover plate 3 onto the surface of the actuator substrate 2 .
- the cover plate 3 is bonded onto the surface of the actuator substrate 2 by using an adhesive, and the channels for liquid discharge are formed. After that, the bonded substrate is separated into parts, and the nozzle plate 4 is bonded at the front end FE of each part of the substrate, to thereby obtain the liquid jet head 1 .
- the conductive film forming step of forming the conductive film 20 by depositing the conductive material, and the electrode forming step of forming the pattern of the conductive film 20 can be performed by an extremely simple method.
- FIGS. 7A , 7 B, 7 C, and 7 D are explanatory diagrams illustrating a manufacturing method for the liquid jet head 1 according to a fourth embodiment of the present invention.
- the conductive film forming step is performed by an oblique deposition step using oblique deposition.
- the first bonding step and the groove forming step are similar to those of the third embodiment, and hence description thereof is omitted.
- FIGS. 7A and 7B are explanatory diagrams illustrating the oblique deposition step of depositing the conductive material obliquely on the surface of the actuator substrate 2 .
- FIG. 7A is a schematic view illustrating oblique deposition
- FIG. 7B is a sectional schematic view of the actuator substrate 2 which has undergone the oblique deposition.
- a depositing device includes an evaporation source 18 and a holder 22 which are accommodated inside a chamber (not shown).
- the holder 22 holds the actuator substrate 2 on the evaporation source 18 side.
- the holder 22 holds the actuator substrate 2 so as to be able to rotate the same about a rotation axis O 1 , and is configured to be rotatable about a perpendicular direction of the evaporation source 18 as a rotation axis O 2 .
- the actuator substrate 2 is set on the holder 22 (at a position on the left side of FIG. 7A ) so that the direction of the evaporation source 18 is substantially orthogonal to a longitudinal direction of the grooves 6 to form an inclination angle ⁇ with respect to a normal n of the surface of the actuator substrate 2 .
- the actuator substrate 2 is rotated about the rotation axis O 1 by 180°, and the actuator substrate 2 is set on the holder 22 (at a position on the right side of FIG. 7A ) so that the direction of the evaporation source 18 is substantially orthogonal to the direction of the grooves 6 to form an inclination angle ⁇ with respect to the normal n of the surface of the actuator substrate 2 .
- the conductive material is evaporated from the evaporation source 18 and deposited on the surface of the actuator substrate 2 and the other side surface of each partition wall 7 .
- the deposition angle ⁇ is set based on the width of the groove 6 and the thickness of the piezoelectric material 10 so that the conductive material is deposited on at least all of the side surfaces of the piezoelectric material 10 forming the partition walls 7 in the drive region DR and extends across the side surfaces of the piezoelectric material 10 and the low-permittivity material 9 .
- Zh may be set to 60 cm and Zx may be set to 29 cm or less.
- the conductive material at a position deeper than substantially half the height of the partition wall 7 that is furthest away from the evaporation source 18 .
- the length of the actuator substrate 2 in the direction orthogonal to the direction of the grooves 6 is 10 cm, three actuator substrates 2 can be aligned between the rotation axes O 1 and O 2 and subjected to deposition simultaneously. That is, it is possible to remarkably improve productivity of the oblique deposition in comparison with a conventional method.
- aluminum is used as the conductive material.
- another metal such as gold and chromium may be used.
- a general condition of the oblique deposition is as follows, the oblique deposition being performed in such a way that the conductive film 20 is deposited at least on the entire side surfaces of the partition walls 7 made of the piezoelectric material 10 and the conductive material is not deposited on the bottom surfaces 12 of the grooves 6 .
- the width of the groove 6 is w
- the height of the partition wall 7 (depth of the groove 6 ) is h
- the height of the boundary between the piezoelectric material 10 and the low-permittivity material 9 of the partition wall 7 is h/2
- the oblique deposition angle (inclination angle) is ⁇ .
- the actuator substrate 2 only needs to be placed at a position at which the oblique deposition angle ⁇ satisfies the following expression (3) with respect to the evaporation source 18 .
- ⁇ 2 ⁇ 1 tan ⁇ 1 ( w/h ) ⁇ tan ⁇ 1 (2 w/h ) (3)
- the oblique deposition angle ⁇ ranges from 12° to 23°.
- Zh expressed in FIG. 7A is 60 cm
- the position Zx of the holder 22 , at which the oblique deposition is possible is in a range of from 12.5 cm to 25 cm, and the actuator substrate 2 only needs to be placed within this range.
- FIG. 7B is a sectional schematic view of the actuator substrate 2 which has undergone the oblique deposition of the conductive material.
- the conductive material is deposited on the surface of the actuator substrate 2 and the top surface and both the side surfaces of each partition wall 7 , to thereby form the conductive film 20 .
- the conductive film 20 on the partition wall 7 is formed deeper toward the bottom surface 12 on the left side surface than on the right side surface.
- the conductive film 20 on the partition wall 7 is formed deeper toward the bottom surface 12 on the right side surface than on the left side surface.
- FIG. 7C is a sectional schematic view of the actuator substrate 2 which has undergone the electrode forming step of patterning the conductive film 20 and forming the drive electrodes 11 from the conductive film 20 formed on each partition wall 7 .
- a pattern of a photosensitive resin film is formed by photolithography, and the conductive film 20 is removed by etching. Further, the conductive film 20 formed on both the side surfaces of the partition wall 7 may be electrically separated into parts by a laser beam and surface grinding instead of by a photo process.
- FIG. 7D is a sectional schematic view of the liquid jet head 1 which has undergone the second bonding step of bonding the cover plate 3 onto the surface of the actuator substrate 2 .
- the cover plate 3 is bonded onto the surface of the actuator substrate 2 by using an adhesive, and the channels for liquid discharge are formed. After that, the bonded substrate is separated into parts, and the nozzle plate 4 is bonded at the front end FE of each part of the substrate, to thereby obtain the liquid jet head 1 .
- the piezoelectric material 10 exhibiting the electrostrictive effect is the same in every partition wall 7 .
- the respective partition walls 7 have a uniform deformation drive amount, with the result that the variations in liquid droplet discharge rate among the channels are reduced.
- the low-permittivity material 9 is interposed between one partition wall 7 and another adjacent partition wall 7 , and hence capacitive coupling between the partition walls 7 is reduced, with the result that it is possible to prevent such a situation that the drive signal leaks to the adjacent partition wall to fluctuate liquid discharge characteristics of the adjacent nozzle.
- FIGS. 8A , 8 B, 8 C, 8 D, and 8 E and FIGS. 9A , 9 B, 9 C, and 9 D are explanatory diagrams illustrating a manufacturing method for a liquid jet head according to a fifth embodiment of the present invention.
- the fifth embodiment is different from the fourth embodiment in that the conductive film 20 formed by the oblique deposition is patterned by the lift-off method, and the other steps are the same as those of the fourth embodiment.
- FIG. 8A is a sectional schematic view of the actuator substrate 2 which has undergone the first bonding step of bonding the piezoelectric substrate made of the piezoelectric material 10 on the surface of the low-permittivity substrate made of the low-permittivity material 9 which is lower in permittivity than the piezoelectric material 10 .
- Materials and the like to be used have been described in the third embodiment.
- FIG. 8B is a sectional schematic view of the actuator substrate 2 which has undergone a photosensitive resin film forming step of forming a photosensitive resin film 21 on the surface of the actuator substrate 2 .
- a resist sheet is used as the photosensitive resin film 21 , and is pasted on the surface of the actuator substrate 2 , to thereby form the photosensitive resin film 21 .
- the photosensitive resin film 21 may be formed by applying a resist layer, instead of the resist sheet, on the surface of the actuator substrate 2 with a spinner or the like.
- FIGS. 8C and 8D illustrate the groove forming step in which the dicing blade 19 is lowered onto the surface of the actuator substrate 2 , and then moved to form the plurality of parallelly aligned grooves 6 .
- the groove forming step is similar to that of the third embodiment.
- FIG. 8E is a top schematic view of the actuator substrate 2 which has undergone a pattern forming step of forming a pattern of the photosensitive resin film 21 .
- the pattern of the photosensitive resin film 21 is formed by photolithography.
- the photosensitive resin film 21 is left in a region from which the conductive material to be deposited in the subsequent oblique deposition step is removed, and the photosensitive resin film 21 is removed from a region in which the conductive material is left.
- the photosensitive resin film 21 is left from the top surface 13 to the right and left end portions of each partition wall 7 . Further, the photosensitive resin film 21 is removed from a region in which each groove 6 and the terminal electrode are formed, and the piezoelectric material 10 is exposed.
- FIGS. 9A and 9B are explanatory diagrams illustrating the oblique deposition step of depositing the conductive material obliquely on the surface of the actuator substrate 2 .
- the oblique deposition step is similar to that of the third embodiment.
- the photosensitive resin film 21 is left on the top surface 13 of each partition wall 7
- the conductive film 20 is formed on the photosensitive resin film 21 .
- the conductive film 20 is formed on both the side surfaces of the partition wall 7 so as to overlap at least the piezoelectric material 10 .
- FIG. 9C is a sectional schematic view of the actuator substrate 2 which has undergone the electrode forming step of forming the electrodes by removing the photosensitive resin film 21 by the lift-off method.
- the photosensitive resin film 21 is removed so that the conductive film 20 is simultaneously removed.
- the conductive film 20 formed on both the side surfaces of the partition wall 7 is electrically separated into parts, to thereby form the drive electrodes 11 .
- the terminal electrodes that are electrically connected to the respective drive electrodes 11 are formed at both the end portions of the surface of the actuator substrate 2 , respectively.
- FIG. 9D is a sectional schematic view of the liquid jet head 1 in which the cover plate 3 is bonded onto the surface of the actuator substrate 2 .
- the liquid jet head 1 is similar to that of the third embodiment.
- the drive electrodes 11 are patterned by the lift-off method after being deposited by the oblique deposition, and hence it is possible to easily form an electrode pattern on both of the side surfaces of each partition wall 7 and the surface of the actuator substrate 2 by a simple step.
- the piezoelectric material 10 exhibiting the electrostrictive effect is the same in every partition wall 7 , and hence the partition walls 7 exhibit a uniform deformation drive amount.
- the low-permittivity material 9 is used, and hence the drive signal does not leak to the adjacent partition wall 7 .
- the pattern forming step for the photosensitive resin film 21 may be performed prior to the groove forming step, and the plurality of grooves 6 may be formed along the pattern of the photosensitive resin film 21 .
- the oblique deposition step for the conductive material is not limited to the methods illustrated in FIGS. 7A , 7 B, 7 C, and 7 D and FIGS. 9A , 9 B, 9 C, and 9 D.
- the lift-off method for the conductive film 20 is not limited to the case of forming the conductive film 20 by the oblique deposition. Needless to say, the lift-off method is applicable to the case of forming the conductive film by sputtering in the third embodiment and another case of forming the conductive film 20 .
- FIG. 10 is a schematic perspective view of a liquid jet apparatus 30 according to a sixth embodiment of the present invention.
- the liquid jet apparatus 30 includes a moving mechanism 43 for reciprocating liquid jet heads 1 and 1 ′ according to the present invention described above, liquid supply tubes 33 and 33 ′ for supplying liquid to the liquid jet heads 1 and 1 ′, and liquid tanks 31 and 31 ′ for supplying liquid to the liquid supply tubes 33 and 33 ′.
- Each of the liquid jet heads 1 and 1 ′ is formed of the liquid jet head 1 according to the present invention.
- each of the liquid j et heads 1 and 1 ′ includes: an actuator substrate including a plurality of grooves aligned parallelly in a surface thereof, and partition walls separating the adjacent grooves; a cover plate bonded onto the surface of the actuator substrate, for covering the grooves; and a nozzle plate including nozzles communicating to the grooves, the nozzle plate being bonded onto an end surface of the actuator substrate.
- the actuator substrate includes a drive region for driving the partition walls so as to deform the same, and for causing liquid filling the grooves to jet from the nozzles.
- Each partition wall in the drive region is made of a piezoelectric material on a top surface side situated above substantially half a height from a bottom surface of the groove to the top surface of the partition wall, and made of a low-permittivity material, which is lower in permittivity than the piezoelectric material, on the bottom surface side situated below substantially half the height.
- the liquid jet apparatus 30 includes a pair of conveying means 41 and 42 for conveying a recording medium 34 such as paper in a main scanning direction, the liquid jet heads 1 and 1 ′ for discharging liquid toward the recording medium 34 , pumps 32 and 32 ′ for pressing liquid stored in the liquid tanks 31 and 31 ′ into the liquid supply tubes 33 and 33 ′ for supply, and the moving mechanism 43 for causing the liquid jet head 1 to scan in a sub-scanning direction which is orthogonal to the main scanning direction.
- a recording medium 34 such as paper in a main scanning direction
- the liquid jet heads 1 and 1 ′ for discharging liquid toward the recording medium 34
- pumps 32 and 32 ′ for pressing liquid stored in the liquid tanks 31 and 31 ′ into the liquid supply tubes 33 and 33 ′ for supply
- the moving mechanism 43 for causing the liquid jet head 1 to scan in a sub-scanning direction which is orthogonal to the main scanning direction.
- Each of the pair of conveying means 41 and 42 includes a grid roller and a pinch roller which extend in the sub-scanning direction and which rotate with roller surfaces thereof being in contact with each other.
- a motor (not shown) axially rotates the grid rollers and the pinch rollers to convey, in the main scanning direction, the recording medium 34 sandwiched therebetween.
- the moving mechanism 43 includes a pair of guide rails 36 and 37 which extend in the sub-scanning direction, a carriage unit 38 which is slidable along the pair of guide rails 36 and 37 , an endless belt 39 which is coupled to the carriage unit 38 for moving the carriage unit 38 in the sub-scanning direction, and a motor 40 for rotating the endless belt 39 via a pulley (not shown).
- the carriage unit 38 has the plurality of liquid jet heads 1 and 1 ′ mounted thereon for discharging, for example, four kinds of liquid droplets: yellow; magenta; cyan; and black.
- the liquid tanks 31 and 31 ′ store liquid of corresponding colors, and supply the liquid via the pumps 32 and 32 ′ and the liquid supply tubes 33 and 33 ′ to the liquid jet heads 1 and 1 ′.
- the respective liquid jet heads 1 and 1 ′ discharge liquid droplets of the respective colors according to a drive signal. By controlling discharge timing of liquid from the liquid jet heads 1 and 1 ′, rotation of the motor 40 for driving the carriage unit 38 , and conveying speed of the recording medium 34 , an arbitrary pattern may be recorded on the recording medium 34 .
- the liquid discharge characteristics of the liquid jet head 1 are equalized in the respective channels.
- the drive signal for driving the channels does not leak to the adjacent channels, and hence high-quality recording of liquid can be performed on the recording medium. Further, it is unnecessary to manufacture the liquid jet head 1 through complicated steps, which may simplify the manufacturing steps and may contribute to cost reduction of the apparatus.
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Particle Formation And Scattering Control In Inkjet Printers (AREA)
Abstract
Description
tan(θ1)=2w/h (1),
tan(θ2)=w/h (2).
θ2<θ<1=tan−1(w/h)<θ<tan−1(2w/h) (3)
Claims (8)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2010121965A JP5588230B2 (en) | 2010-05-27 | 2010-05-27 | Liquid ejecting head, liquid ejecting apparatus, and method of manufacturing liquid ejecting head |
JP2010-121965 | 2010-05-27 |
Publications (2)
Publication Number | Publication Date |
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US20110292135A1 US20110292135A1 (en) | 2011-12-01 |
US8480210B2 true US8480210B2 (en) | 2013-07-09 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US13/134,038 Active US8480210B2 (en) | 2010-05-27 | 2011-05-26 | Liquid jet head, liquid jet apparatus, and manufacturing method for the liquid jet head |
Country Status (5)
Country | Link |
---|---|
US (1) | US8480210B2 (en) |
EP (1) | EP2390094B1 (en) |
JP (1) | JP5588230B2 (en) |
KR (1) | KR20110130355A (en) |
CN (1) | CN102294897B (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5891096B2 (en) * | 2012-04-12 | 2016-03-22 | エスアイアイ・プリンテック株式会社 | Liquid ejecting head manufacturing method, liquid ejecting head, and liquid ejecting apparatus |
CN105142914B (en) * | 2013-03-15 | 2017-03-15 | 柯尼卡美能达株式会社 | Ink gun and its manufacture method and ink-jet printer |
JP6139319B2 (en) * | 2013-07-30 | 2017-05-31 | エスアイアイ・プリンテック株式会社 | Liquid ejecting head and liquid ejecting apparatus |
JP6450079B2 (en) * | 2014-03-12 | 2019-01-09 | セイコーインスツル株式会社 | Head chip manufacturing method, liquid jet head, and liquid jet apparatus |
JP2015171804A (en) * | 2014-03-12 | 2015-10-01 | セイコーインスツル株式会社 | Manufacturing method of head chip, liquid jet head, and liquid jet device |
CN103879148A (en) * | 2014-03-14 | 2014-06-25 | 常熟印刷厂有限公司 | Printing head |
JP6393130B2 (en) | 2014-09-12 | 2018-09-19 | エスアイアイ・プリンテック株式会社 | Liquid ejecting head, liquid ejecting apparatus, and method of manufacturing liquid ejecting head |
JP6393180B2 (en) * | 2014-12-16 | 2018-09-19 | エスアイアイ・プリンテック株式会社 | Liquid ejecting head, liquid ejecting apparatus, and method of manufacturing liquid ejecting head |
JP6573825B2 (en) * | 2015-11-27 | 2019-09-11 | エスアイアイ・プリンテック株式会社 | Liquid ejecting head and liquid ejecting apparatus |
JP2021133647A (en) * | 2020-02-28 | 2021-09-13 | キヤノン株式会社 | Liquid discharge head |
GB2599902A (en) * | 2020-10-11 | 2022-04-20 | Mesa Tech Ltd | Printing apparatus and method |
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- 2010-05-27 JP JP2010121965A patent/JP5588230B2/en not_active Expired - Fee Related
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- 2011-05-26 US US13/134,038 patent/US8480210B2/en active Active
- 2011-05-26 KR KR20110050012A patent/KR20110130355A/en not_active Application Discontinuation
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Also Published As
Publication number | Publication date |
---|---|
EP2390094A1 (en) | 2011-11-30 |
CN102294897A (en) | 2011-12-28 |
US20110292135A1 (en) | 2011-12-01 |
CN102294897B (en) | 2015-09-30 |
KR20110130355A (en) | 2011-12-05 |
EP2390094B1 (en) | 2015-09-23 |
JP5588230B2 (en) | 2014-09-10 |
JP2011245768A (en) | 2011-12-08 |
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